It’s no secret that the former Magnum P.I. star Tom Selleck has been having a rough go of it in Hollywood as of late. Last year, CBS cancelled his long-running police procedural drama Blue Bloods.

“Magnum, P.I.” aired from 1980 to 1988. Over 50 million people viewed its final episode. The show starred, clockwise from left, Larry Manetti as Rick Wright, John Hillerman as Higgins, Roger E. Mosley ...